The goals of this project are to develop, evaluate, and disseminate an interactive, Internet-based program that provides a brief motivational intervention for adolescent smokers, the Adolescent Smoker's Check-up (ASCU). The content of the ASCU will be modeled on a face-to-face brief intervention for adolescent smokers that has demonstrated efficacy. The structure of the program will be similar to a computer-based brief motivational intervention for drinkers, the Drinker's Check-up, which is currently being evaluated in a controlled clinical trial. The ASCU will consist of integrated Assessment, Feedback, Decision Making, Follow-up and Administrator modules. It will use the FRAMES elements common to effective brief interventions. The Follow-up component will have extensive outcome report capabilities that could be used for program evaluation. The goals of Phase I are to develop a limited prototype of the first three modules and evaluate its technical merit and feasibility. The goals of Phase II include completing the prototype, creating a Follow-up module, beta testing, then a controlled clinical trial to assess its efficacy. The public health concerns are far reaching. Despite spending millions of dollars on adolescent smoking prevention programs, approximately one third of American teens smoke on a regular basis and roughly 90 percent of adult smokers report onset of regular smoking during adolescence. Recent literature suggests that nearly six million adolescents are regular smokers and an additional three thousand teens become regular smokers each day. The results from contingency-based approaches (i.e. juvenile smoking courts), skills building programs (i.e., "just say no"), or other extrinsically driven techniques do not seem to be effective with this population. The ASCU will be designed for teens to enhance their intrinsic motivation to quit smoking. This program could be an effective approach to adolescent smoking cessation either as a stand-alone intervention or as a pre-treatment adjunct to existing school, community, or judicial systems.